Considering how many complaints there have been about lens creep on the 18-200 VR and considering how many Nikon must have sold, I can imagine a lot of people in Nikon service looking forward to a revision.
There are a lot of potential customers for the 70-200 that are on the fence because of the slight vignetting of the current version on FX. It is without question a great lens already, but from a business perspective I think there is more dollar volume in 70-200 VR IIs than there will be in two new primes combined.
Let's also not forget that the 18-200 accounted for the majority of "dead battery" problems. Again looking at it from a business perspective, updating service prone units make sense. It will be interesting to see what is actually announced.